Blood collection is always important, particularly in times of emergency (immediate use), but whole blood may only be stored for about 30 days before it is “outdated”. For long term storage, the ability to separate the whole blood into its major components (white blood cells, platelets, red blood cells and plasma) is of paramount importance because the long term storage condition for each component is different in terms of temperature and storage media. The most important component separations occurring after collection is the separation of red blood cells (RBC), white blood cells (WBC), platelets, and plasma from one another. Within the WBC it is sometimes important to separate the granulocytes from the lymphocytes and monocytes. After separation and extraction of particular components, a fraction of the blood may be returned to the patient.
It is possible to separate the various components of whole blood either under or after centrifugation, due to their differing densities. Some prior art methods, such as that in U.S. Pat. No. 4,120,448, utilize a chamber connected to a centrifuge. The centrifuged blood separates in the chamber, and a plurality of collection means are positioned at various locations in the chamber corresponding to the areas where each component congregates, which is density-dependent.
The present (prior art) technique for sequestering white blood cells from whole blood: requires skilled technicians, is labor intensive in that it requires 16 steps conducted over the span of one hour, and produces inconsistent results because of the requirements placed on the technician in the exercise of technique. Most significantly, however, the 16 step present technique is “open”; that is, the blood product is processed in a manner that does not maintain the sterility of the product because the need to obtain samples or add sedimenting agents or cryoprotectants at the various stages of production can not be accomplished with allowing the outside environment access to the interior, meaning potential contamination of the product:
The 16 steps are:
1. Collect placental blood into collection bag (range 60-200 ml).
2. Add HES to collection bag (20% v/v).
3. Load collection bag into special centrifuge cup supports.
4. Centrifuge at 50 G for 13 min. to raise WBC from RBC (up to 6 units at one time).
5. Spike or sterile dock collection bag to expressor and processing bag set to scale.
6. Gently transfer collection bag to expressor and processing bag set to scale.
7. Express off WBC rich plasma and 10-15 ml of the top layer of RBC into processing bag—leaving excess RBC.
8. Remove collection bag with excess RBC.
9. Load processing bag set in special centrifuge cup supports.
10. Centrifuge processing bag set at 400 G for 10 min. (up to 6 units at one time).
11. Gently transfer processing bag to expressor.
12. Express off excess plasma leaving 20 ml WBC concentrate.
13. Remove excess plasma bag from processing set.
14. Add 5 ml cryoprotectant to WBC in processing bag at 4° C.
15. Transfer cryoprotected WBC to freezing bag.
16. Tube seal and separate freezing bag from processing bag.
The following prior art reflects the state of the art of which applicant is aware and is included herewith to discharge applicant's acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as disclosed in greater detail hereinafter and as particularly claimed.
PAT. NO.ISSUE DATEINVENTOR4,120,448Oct. 17, 1978Cullis4,720,284Jan. 19, 1988McCartyDes. 314,824Feb. 19, 1991Moon5,674,173Oct. 7, 1997Hlavinka et al.5,723,050Mar. 3, 1998Unger et al.5,792,038Aug. 11, 1998Hlavinka5,921,950Jul. 13, 1999Toavs et al.6,315,706Nov. 13, 2001Unger et al.6,348,031Feb. 19, 2002Unger et al.6,652,475Nov. 25, 2003Sahines et al.WO95/01842Published: Jan. 15, 1995Unger
The prior art references listed above but not specifically described teach other devices for blood processing and further catalog the prior art of which the applicant is aware. These references diverge even more starkly from the reference specifically distinguished above.